they gonna make sure your engine doesnt have fun little peices of metal in it too?
magnetic drain plug… :ponder
Taken from dealer TSB reference catalog…
We have received several inquires into the engine oil requirements for 2005MY and later vehicles. The owners’ manual refers to ILSAC and API oil grades, but you may ask “what are they”?
There are several organizations that develop, categorize, and license oil grades. The Society of Automotive Engineers (SAE) and the American Society of Testing Materials (ASTM) are involved in the performance parameters of oil development, but we will limit this discussion to the ILSAC and API organizations.
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ILSAC – International Lubricant Standardization and Approval Committee. This committee is made up of American and Foreign Automotive Manufacturers that develop the standards/requirements for oil grades.
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API – American Petroleum Institute. This organization licenses the approved oil with an API certification mark (‘starburst’ mark) which identifies the oil as meeting the current requirements set forth by ILSAC. The API also has a symbol of the ‘donut’ which contains their own API category identification, oil viscosity, and energy conserving designation, if applicable. The API has their own set of categories to identify oil grades. Prior to ILSAC’s inception, the API was the only organization to develop oil grade standards.
Since ILSAC’s existence in 1992, they have developed 4 different categories of oil grades, they are:
GF-1 first appeared in 1996
GF-2 first appeared in 1997
GF-3 first appeared in 2001
GF-4 first appeared in 2004
The categories are backwards-compatible with all previous categories, however they are not cross-compatible. For instance, GF-4 can be used in-lieu of GF-3, but GF-3 cannot be used when GF-4 is required.
API has a total of 11 gasoline engine categories in their history, starting with SA through SM (SI and SK have been omitted from the sequence).
Since the new GF-1 category, the API has worked to standardize their categories with the ILSAC standards. Although the categories are not entirely similar, they are compatible up to the current category. API has a separate energy conserving designation “Energy Conserving” which must be present for compatibility with the ILSAC categories.
Compatibility Chart
GF-1 / SH (Energy Conserving)
GF-2 / SJ (Energy Conserving)
GF-3 / SL (Energy Conserving)
GF-4 / SM (Energy Conserving)
All 2005MY:
Oil grade: ILSAC: GF-3 - or - API: SL (Energy Conserving) if not available SJ (Energy Conserving) may be used, SL is still the preferred grade.
All 2006MY and later:
Oil grade: ILSAC: GF-4 - or - API: SM (Energy Conserving)
GF-3 cannot be used in any 2006MY or later Subaru vehicles. The GF-4 category oil has the lowest phosphorus content of any oil preceding it. Phosphorus has been found to reduce the effectiveness and longevity of the emission system. There are several other important changes that were implemented to increase fuel economy and overall longevity of the engine.
Although most oils will contain both the GF-4 and SM (Energy Conserving) designation, it only needs to meet “GF-4” OR “SM”.
Currently the FHI/SIA factory fill oil is 0W-20 mineral oil for the H4 SOHC(w/o VVL) and 5W-30 mineral oil for all others. The oil is designated as SM and GF-4 and is manufactured by Shin-Nihon Petroleum (FHI) and Shell (SIA).
Clarifications:
- Synthetic oil can be safely used provided the viscosity and oil grade classifications as noted in the Owners Manual are used. The oil change interval noted in the maintenance schedule must still be adhered to.
- Severe Driving Conditions will require the oil change interval to be increased to 3,750 miles or 3.75 months. New for 2008: All turbocharged models are considered to be operated under severe driving conditions and require the oil interval of 3,750 miles or 3.75 months.
Summary:
Use a GF4/SM oil if you have a 2006 or later Subaru
change your oil at 3750 miles
use synthetic if you want
List of GF-4 (or SM) approved oils:
Castrol Syntec 5w30
Redline Synthetic 5w30
Pennzoil Platinum 5w30
Mobil1 (classic, non-supersyn) 5w30
What is NOT GF-4 (or SM) approved?
-Royal Purple
-Motul
-Mobil1 SuperSyn
Okay…so I was a little dramatic in saying all synthetic is frowned upon…but as you can see they are fussy…and I believe the OP was running…drumroll…Royal Purple :nono
I’d be damned if I paid for Royal Purple for my car. Straight up Castrol for $2 a quart changed every 200-500 miles. Clean oil > *
Justin, what do you use in your STi?
WOW! way overkill, imo
:+1 By inustry standarts, even changing regular oil at 3K miles is considered overkill.
Technology gets better with age Shawn not worse :ponder
Does it still come out golden?
200-500 miles = 4-8 months for my car. 
Rule of thumb is change before 6 months (I have heard 3 months) regardless of mileage.
Might as well keep it empty and just put in oil before you’re going to drive it :tong
Dosn’t get fresher than that. :lol
you sneaky bastard
Yea. Remember, you can throw out industry standards when talking about a modified car in regards to its fuel system. Oil with fuel injected = BAD.
On a totally stock car, hell, I’d go 3K without worries but the amount of money it takes to replace the oil means nothing to me if it’s done early. I just refuse to pay for synthetic or expensive shit like Royal Purple when 1) I change oil every very often 2) I don’t think it makes that much of a difference as long as it is clean.
I knew it would bait someone. 
Yea, for the common car, that’s a bit overkill but do what makes ya comfortable.
Castrol Syntec FTW!
5w30 conventional
20W50. I like the oil pressure.
There is nothing wrong with Royal Purple. Additionally there is nothing wrong with running Synthetic oil, as noted in your post, PROVIDED it meets the minimum API and ILSAC specifications. Ford went through a lot of this shit when they changed to a 5w20 standard oil in their motors. People were running 5w20 generic crap off the shelf that didn’t meet the minimum protection standards. As a result, people were experiencing excessive wear issues on lower mileage vehicles when changing oil within factory specs.
You can see the meat of this argument by vieweing results of the ASTM 4 ball wear test.
Oils with a “higher” classification, such as SJ, SM, and so forth, have higher marks for pressure point protection, shear, stability, oxidation and so forth.
If subaru states the minimum standard is SM, then use synthetic oils with SM or greater. Talking about brands is essentially splitting hairs. All brands will have differing results with regard to element analysis and product behavior under usage, but those results are what set oils apart for protection levels BEYOND the recommended factory maintenence intervals, or beyond estimated powerplant lifetimes.
Don’t you ever argue with me again, sexy.
bows to Redroof
Surprising to not hear people mention Mobile1. Big thread on several forums where they changed the formula for it and it got people all pissed. This was several months ago to a year ago so I am not sure the status now.
Mobile 1 Fully Synthetic 10W-30 changed every 2000 miles.
yup… mobile 1 is the suck. I’ve read countless threads on the evo forums about it. I’m giving amsoil 10w-30 a try when spring rolls around.
I don’t have any personally experience since I haven’t changed yet
yessir.